Which of these is NOT a core benefit of Medicare Plan A$?$

A$)$ The $20\%$ co$-$payment for Part B after the annual deductible

B$)$ The Medicare Part A co$-$payment from the $61$st to the $90$th day of hospitalization in each Medicare benefit period

C$)$ All the blood needed by a policy owner during a surgical procedure

D$)100\%$ of eligible inpatient hospital expenses not covered by Medicare, up to a maximum of $365$ days